It is common practice in the automotive art to include a headlight switch with a buzzer circuit for turning the parking and headlights "on" and "off" by means of a longitudinal pulling or pushing action, respectively, which switch is also combined with a rheostat for dimming or brightening the panel lights on the dashboard by a circular, twisting or rotary motion.
Likewise, this switching structure is used as well to turn a light "on" and "off," such as for example the interior dome light. The function of the dome light switch is to, for example, turn off the dome light circuit, when one or more of the vehicle's doors or tailgate is open, by rotating the shaft of the overall switch to the extreme clockwise position (as viewed from the front).
It has been the further practice to have such a composite switch be integrated in its design and occupy a relatively limited and particularly sized space with standardized mounting brackets located in particular locations, so that the composite switch can be mounted in a number of different cars within a car maker's line(s). As can be seem from the perspective of FIG. 1A, the rheostat 3 is centrally located between the electrical switching component 2 and the front bracketed portion 4, with respect to the longitudinal dimension.
In the prior art design, particularly for example in the "Chrysler" switch for this purpose, the "on"/"off" switch for the dome light was mounted on the side, exterior of the otherwise in-line construction, with the prior art switch having an exposed arm extending generally longitudinally and parallel to the center axis of the switch with its front end bent inwardly to position its distal tip adjacent to the side of the rheostat, so that a projection on the rheostat would cause the switch arm to be moved, breaking the normal electrical contact within the switch.
Such a design added to the bulk of the main switch body and caused significant alignment problems. Additionally, by extending off of the side of the main body of the switch, the dome light switch became more vulnerable to damage in handling and assembling into the vehicle. Sometimes the exposed switch arm became bent or misaligned, failing to thereafter engage the rheostat.
It additionally had excessive tolerance stack-ups on component parts. Also, the switch arm required ultrasonic welding between it and its associated terminal, a relatively difficult process.